package com.itheima.reggie.controller;

import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

//文件上传和下载
@RestController
@Slf4j
@RequestMapping("/common")
public class CommonController {
    @Value("${reggie.path}")
    private String basePath;
    //文件上传
    @PostMapping("/upload")
    public R<String> upload(@RequestParam("file") MultipartFile File){
        //注 : file是一个临时文件，需要指定储存位置，否则本次请求结束后文件会删除
        //原始文件名
        String originalFilename = File.getOriginalFilename();
        String fileindex = originalFilename.substring(originalFilename.lastIndexOf("."));
        //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String filename = UUID.randomUUID().toString() + fileindex;

        //创建目录对象
        File dir = new File(basePath);
        if(!dir.exists()){
            //目录不存在则创建
            dir.mkdirs();
        }

        try {
            //将临时文件转存到指定位置
            File.transferTo(new File(basePath + filename));
        } catch (IOException e) {

            throw new RuntimeException(e);


        }
        return R.success(filename);
    }

    //文件下载
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response){

        try {
            //输入流，通过输入流读取文件内容
            FileInputStream fileInputStream = new FileInputStream(new File(basePath+name));
            //输出流，通过输出流将文件写回浏览器，在浏览器展示图片
            ServletOutputStream outputStream = response.getOutputStream();
            response.setContentType("image/jpeg");
            byte[]bytes=new byte[1024];
            int len = 0;
            while((len = fileInputStream.read(bytes)) != -1){
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }
            outputStream.close();
            fileInputStream.close();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }



    }
}
